ABSTRACTThe study examines the private sector as the engine of economic growth and development in Nigeria. A model was specified and data were collected from the period of 1980-2010. The method used in this research work is the ordinary least square (OLS) regression model and variables which are: gross domestic product (GDP) as the dependent variable while foreign private investment (FPI), domestic private investment (DPI), total private savings (TPS), and total bank loans (TBL) are the independent variables and are all significant except total private savings that is insignificant. From the regression result, the following findings were made The estimate coefficients which are 0.8999687 {FPI} shows that a 1 percent increase in foreign private investment will cause 89.9 per cent increase in GDP, 0.0851059 {DPI} shows that a 1 percent increase in domestic private investment will cause an 8.5 per cent increase in GDP, 0.2444129 {TBL} shows that a 1 percent increase in total bank loans will cause 24 per cent increase in GDP. – 0.0268498 {TPS} shows that a 1 percent increase in total private savings will cause 2.6 per cent decrease in GDP.. I recommend that there should be policies that will attract foreign investors; such policies could be the reduction of corporate tax rate. Incentives should be given to local investors to enable them compete with foreign investors world-wide. Policies also should be made against the transfer of capital and profit from Nigeria to foreign countries as it drains the income meant for national development. The government should also maintain political stability in the economy because unstable environment discourages investors.